Many reported risks and hazards in hemodialysis are associated with water quality, including pyrogenic contamination. The typical patient on dialysis is exposed to between 30 to 40 times the amount of water to which a member of the general population is exposed. Thus, the quality of hemodialysis water is obviously very important. Current practices in hemodialysis systems do not guarantee pyrogen-free water. Several drawbacks exist in using available procedures to achieve pyrogen-free water: (i) addition of chemicals, which have to be monitored and destroyed before the water contacts the dialysis membrane. Otherwise, the chemicals may come in contact with the patient about blood; (ii) formation of toxic by-products from the reaction of pyrogens with the disinfectant; (iii) no on-line means of providing pyrogen-free water (i.e., batch-mode operation), and (iv) cost. This project concerns the development and evaluation of an efficient, fast, and cost-effective photoreactor to supply pyrogen-free water on-line in hemodialysis system. The disinfecting agents are short-lived hydroxyl radicals, one of the strongest oxidants known, which are produced in-situ, and consumed inside the photoreactor. During the Phase II project, an automated prototype system will be developed and integrated into a hemodialysis system. Technical and cost evaluations will be carried out to provide the foundation for a commercial system. PROPOSED COMMERCIAL APPLICATION: Pyrogen-free water is required in all hemodialysis systems. In addition, this technology will find application in other areas of the medical industry: large quantities of pyrogen-free water are required for intravenous infusion fluids, fluids for injection and for irrigation in operating rooms. Also, other industries, such as the hydroponics industry need sterile water.